RAPID TECHNIQUES FOR DETERMINATION OF FREE LIME AND FREE MAGNESIA IN CEMENT CLINKER AND PORTLANDITE IN HYDRATES

Free lime is estimated by refluxing a sample quantity of ground clinker or cement in an alcoholic solution of ammonium acetate under gentle boiling. The resultant extract is filtered and titrated with EDTA to provide free CaO content. The method has been termed the Ammonium Acetate Method (AAM). The same technique is also applicable to the estimation of portlandite in hydrated cement. Alcoholic solution prevents cement hydrolysis. Free MgO is extracted from clinker in the form of a double salt through reaction with ammonium nitrate. Use of ethanol again prevents hydrolysis of MgO present as solid solution in cement compounds. The technique has been termed the Ammonium Nitrate Method (ANM). The developed methods have been compared with existing standard procedures.